Embodiments of the present disclosure relate to a semiconductor device and a method for fabricating the same and, more particularly, to a semiconductor device having reduced parasitic capacitance between bit lines or storage nodes and a method for fabricating the same.
As integration of semiconductor devices increases, the spacing between metal lines formed on the same plane is reduced. However, when the spacing between the metal lines is reduced, crosstalk between the metal lines may occur, and parasitic capacitance increases between metal lines, which are isolated by insulation films. Therefore, electrical signals that are sent through the metal lines may not transmit properly and/or the transmission speed of electrical signals may be reduced.
Since a plurality of metal lines is formed in a small space, the width of the metal lines is reduced and resistance increases due to the reduction in thickness of the metal lines. Resistance and parasitic capacitance of the metal lines increases overall resistance, disturbing the flow of electrical signals and delaying signal transmission due to phase changes. Since signal transmission delay deteriorates semiconductor device efficiency and performance, it must be suppressed. Accordingly, a method for reducing parasitic capacitance and resistance of the metal lines is needed. One method for reducing parasitic capacitance between metal lines is reducing the width of metal lines and increasing the spacing between the metal lines. However, since resistance depends on metal line thickness, there is a limit on how thin the metal lines can be formed. Additionally, increasing the spacing between metal lines conflicts with the goal of increasing integration density.